The purpose of this study is to determine how, under conditions of insulin resistance, blood levels of the hypotensive lipid, platelet-activating factor (PAF) may be related to hypertension, platelet aggregation and selected coagulation factors and how urinary PAF may be related to renal function and urinary albumin excretion. The protocol proposes to study these phenomena in African- and Mexican-Americans, groups which are highly associated with hypertension.